Vehicles operating in an autonomous mode (e.g. driverless) can relieve occupants, especially the driver, from some driving-related responsibilities. When operating in an autonomous mode, the vehicle can navigate to various locations using onboard sensors, allowing the vehicle to travel with minimal human interaction or in some cases without any passengers.
Motion planning and control are critical operations in autonomous driving. When a vehicle is operating in an autonomous mode, however, certain events may occur that require immediate action. For example, in an emergency situation when there is a hardware or software failure for a component required for the autonomous driving system, a human driver may be expected to take over control of the vehicle. However, immediate human invention may not always be feasible in certain circumstances such as when a driver may not be alerted in time, or when a human driver may not be able to react in a sufficiently immediate manner. Accordingly, even in emergency situations, there may be instances where autonomous control may still be the most effective course of action.